Conventionally, facsimile apparatus contains both signal transmission and signal reception sections. The structure of the signal transmission section includes feed rollers for feeding a number of documents one by one to a predetermined station inside the apparatus, transfer rollers for transferring the documents fed by the feed rollers, and pressure rollers for closely contacting the surfaces of the documents with an image sensor for scanning the information recorded on the documents. The structure of the signal receiving section includes transfer rollers for transferring heat-sensitive paper, a thermal print head for thermally recording received data on the heat-sensitive paper, a cutter for cutting the heat-sensitive paper to the amount of the received data, and discharge means for discharging the cut paper.
In designs of document feeders used in the signal transmission section the document should be in exceptionally close contact with an image sensor because any gap existing between the image sensor and the document causes a lack of focus of the image sensor to result in an unclear reproduced image. Consequently, a pressure roller is required to press documents against the image sensor.
Moreover, the gear structure of designs for conventional document feeders comprises a drive gear directly connected with a motor for driving a series of idler gears engaged with a feed gear for driving a feed roller. Additionally, a first transfer gear is connected with the feed gear via an idler gear for driving a first transfer roller while an idler gear is to rotate the first transfer roller in the same direction as the feed roller and increase the line speed of the first transfer roller. The first transfer gear is engaged with a pressure gear to drive a pressure roller. The pressure gear is in turn engaged with a second transfer gear to drive a second transfer roller. Thus, the gear and roller structure is made unduly complicated in order to reduce the bulk of the facsimile apparatus. Furthermore, the rotational speeds of the first transfer roller, pressure roller and second transfer roller should be the same.
U.S. Pat. No. 5,077,618 issued Dec. 31, 1991 to Sakai et. al. simplifies a facsimile apparatus by providing a single conveyor roller, i.e. pressure roller, above which an image sensor is set and below which a printing head is set. The apparatus provides a document transferring system which includes: feeding rollers; a single pressure roller driven from a motor via a first drive gear, a reduction gear and a second drive gear; and discharge rollers. The gear configuration for driving the feeder rollers and the discharge rollers is not disclosed.
The present invention simplifies the document transferring system of Sakai et. al. by requiring fewer components, thus improving efficiency and saving manufacturing costs, replacement pan costs, and maintenance costs.